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Table 2 Association of reproductive characteristics with all-cause mortality in the EPIC study

From: Reproductive factors and risk of mortality in the European Prospective Investigation into Cancer and Nutrition; a cohort study

Variable Value Cases / non-cases Model 1 HRa (95 % CI) Model 2 HRb (95 % CI)
Parous No 2,220 / 45,746 1.00 (reference) 1.00 (reference)
  Yes 11,757 / 254,871 0.80 (0.76–0.83) 0.80 (0.76–0.84)
Number of FTPsc 1 2,307 / 45,881 1.00 (reference) 1.00 (reference)
  2 5,026 / 122,430 0.87 (0.83–0.91) 0.91 (0.86–0.96)
  3 2,529 / 56,316 0.83 (0.79–0.88) 0.87 (0.82–0.92)
  4 1,047 / 16,278 0.97 (0.90–1.04) 0.98 (0.91–1.06)
  5 350 / 4,448 0.97 (0.87–1.09) 0.97 (0.86–1.09)
  ≥6 237 / 2,290 1.09 (0.95–1.25) 1.08 (0.94–1.24)
  P for trendd 0.91 0.79
Age at first FTP, yearsc ≤20 1,812 / 37,390 1.30 (1.23–1.38) 1.10 (1.04–1.17)
  21–23 3,121 / 68,203 1.13 (1.07–1.19) 1.05 (1.00–1.11)
  24–25 2,173 / 49,889 1.02 (0.97–1.08) 1.00 (0.95–1.06)
  26–30 3,287 / 72,649 1.00 (reference) 1.00 (reference)
  ≥31 1,281 / 25,749 1.08 (1.01–1.15) 1.08 (1.01–1.16)
Breastfeedingc Never 1,721 / 36,691 1.00 (reference) 1.00 (reference)
  Ever 9,148 / 202,910 0.88 (0.83–0.93) 0.92 (0.87–0.97)
Breastfeeding, monthse ≤1 949 / 20,021 1.00 (reference) 1.00 (reference)
  >1 to ≤3 1,753 / 39,935 1.01 (0.93–1.09) 1.01 (0.93–1.09)
  >3 to ≤6 1,846 / 41,685 0.94 (0.87–1.02) 0.97 (0.89–1.05)
  >6 to ≤12 2,224 / 47,802 0.90 (0.83–0.98) 0.95 (0.88–1.03)
  >12 to ≤18 986 / 23,319 0.81 (0.74–0.89) 0.88 (0.80–0.97)
  >18 1,276 / 27,949 0.88 (0.80–0.96) 0.97 (0.89–1.07)
  P for trendd 0.013 0.85
Infertilityf No 8,958 / 199,770 1.00 (reference) 1.00 (reference)
  Yes 360 / 9,869 1.06 (0.95–1.18) 1.06 (0.95–1.18)
OC use in never or former Never 6,379 / 100,292 1.00 (reference) 1.00 (reference)
smokers at baselineg Ever 3,736 / 140,642 0.90 (0.85–0.94) 0.90 (0.86–0.95)
  Formerh 3,475 / 122,414 0.89 (0.85–0.94) 0.90 (0.86–0.95)
  Currenth 140 / 12,959 0.89 (0.74–1.07) 0.92 (0.76–1.11)
Duration OC use, yearsg,i ≤1 679 / 25,490 1.00 (reference) 1.00 (reference)
  >1 to <5 721 / 30,600 0.99 (0.89–1.10) 0.99 (0.89–1.11)
  5 to <10 705 / 30,859 0.95 (0.85–1.06) 0.96 (0.86–1.07)
  10 to <15 616 / 21,267 1.05 (0.94–1.18) 1.06 (0.94–1.18)
  ≥15 526 / 18,583 1.02 (0.90–1.15) 1.02 (0.91–1.16)
  P for trendd 0.36 0.32
Age at menarche, years <12 1,977 / 45,763 1.00 (reference) 1.00 (reference)
  12 2,714 / 65,654 0.92 (0.86–0.97) 0.95 (0.89–1.01)
  13 3,378 / 79,701 0.88 (0.84–0.94) 0.92 (0.87–0.98)
  14 3,224 / 66,159 0.89 (0.84–0.95) 0.93 (0.88–0.98)
  ≥15 2,774 / 47,743 0.88 (0.82–0.93) 0.90 (0.85–0.96)
  P for trendd 0.004 0.038
Age at natural menopause, yearsj ≤45 1,080 / 12,399 1.15 (1.07–1.24) 1.09 (1.01–1.17)
  46–50 2,427 / 32,488 1.00 (reference) 1.00 (reference)
  51–52 1,064 / 14,537 0.88 (0.82–0.95) 0.91 (0.85–0.99)
  53–55 1,003 / 12,753 0.86 (0.80–0.93) 0.92 (0.85–0.99)
  >55 339 / 3,287 0.90 (0.80–1.01) 0.95 (0.85–1.07)
  P for trendd <0.001 <0.001
Total ovulatory lifespan, yearsk,l 0–22 1,180 / 56,387 1.00 (reference) 1.00 (reference)
  22–29 1,621 / 53,629 0.96 (0.89–1.05) 0.99 (0.91–1.07)
  29–34 2,148 / 52,270 0.92 (0.84–0.99) 0.96 (0.89–1.04)
  ≥34 3,115 / 51,923 0.89 (0.82–0.97) 0.98 (0.91–1.06)
  P for trendd 0.004 0.86
Oophorectomyl No 11,167 / 266,535 1.00 (reference) 1.00 (reference)
  Yes 1,202 / 18,603 1.05 (0.98–1.11) 1.01 (0.93–1.10)
Hysterectomyl No 10,606 / 257,298 1.00 (reference) 1.00 (reference)
  Yes 1,972 / 30,608 1.01 (0.96–1.06) 1.00 (0.94–1.05)
  1. FTP, Full term pregnancy; OCs, Oral contraceptives
  2. aCox regression stratified by age (continuous) and study centre
  3. bCox regression adjusted for menopausal status (where applicable) (premenopausal [Ref], perimenopausal/unknown menopause, postmenopausal and surgical postmenopausal [bilateral oophorectomy]), body mass index (<23, 23–24.9 [Ref], 25–29.9, 30–39.9, 40+ kg/m2), physical activity index (inactive [Ref], moderately inactive, moderately active, active, unknown), education status (none/primary school [Ref], technical/professional school, secondary school/longer education including university, or unknown), smoking status/intensity (never [Ref], current 1–15 cigarettes/day, current 16–25 cigarettes/day, current 26+ cigarettes/day, former quit ≤10 years, former quit 11–20 years, former quit >20 years, current pipe/cigar/occasional smoker, current/former missing timing, unknown), smoking duration (<10 [Ref], 10 to <20, 20 to <30, 30 to <40, 40+ years, unknown), and stratified by age and study centre
  4. cRestricted to parous women. A FTP was defined as live births and stillbirths
  5. dP for trend values are based on continuous variables: the number of FTPs was modelled as 1 to ≥10; age at menarche as ≤8, 9–19, ≥20; age at menopause as <35, 35–60, >60
  6. eAmong parous women who had ever breastfed (sum of all FTPs)
  7. fDenmark, Sweden, Norway, and the Bilthoven (Netherlands) study centre were excluded since data were not available
  8. gRestricted to participants who were never or former smokers, therefore models were adjusted for the same factorsb and a modified smoking status/intensity variable (never [Ref], former quit ≤10 years, former quit 11–20 years, former quit >20 years, former missing quit years, occasional smoker)
  9. hDoes not add up to the total number of OC users because 3.7 % of OC users were missing their timing of use
  10. i Among ever users of OCs
  11. jAmong postmenopausal women; excluded participants from Sweden (no data for hysterectomy/oophorectomy), those who reported a surgical menopause (hysterectomy and/or unilateral/bilateral oophorectomy), or if information on surgical menopause was missing
  12. kThe total ovulatory lifespan is the difference between the age at natural menopause and the age at menarche for postmenopausal women, or the difference between the age at recruitment and the age at menarche for premenopausal/perimenopausal/unknown menopausal status women, minus the amount of time that a woman was pregnant (number of full term pregnancies × nine months) and/or used OCs
  13. lSweden was excluded from these comparisons (no data for hysterectomy/oophorectomy), therefore age at natural menopause could not be determined